A major goal of The International Fertiliser Association (IFA) and its 500 global members is to improve nutrient efficiency, enabling farmers to increase their yields while simultaneously reducing fertiliser inputs.
The nutrients most under scrutiny are nitrogen and phosphates because they are needed in large quantities to optimise plant growth, although potash and sulphur are also at issue.
At Fertco, we’ve been promoting the use of efficient fertilisers for more than 25 years and are continually looking for innovative products that are aligned with the IFA’s goals.
Reduced solubility
One proven way to increase nutrient efficiency is to use fertilisers that are less soluble than their conventional counterparts. Such fertilisers are more efficient because the nutrients aren’t released into the soil all at once. Instead, they’re released gradually to feed the pasture or crop as it grows. So less of the nutrient that is applied is wasted.
One excellent example is polymer-coasted urea (PCU). The reduced solubility of PCU is due to a biodegradable polymer-coating on the urea granule. This coating controls the rate at which moisture enters the granule, dissolves the urea inside, then releases it to the soil for plants to take up. Because the process depends on the moisture levels in the soil, it can take up to several months to complete. So, the nutrients stay protected in the granule rather than being wasted to the environment.
Another proven example is the use of dicalcic phosphate as an alternative to superphosphate. The reduced water-solubility of dicalcic phosphate means that the nutrients are released more slowly. The nutrient-release occurs through microbial activity in the soil which increases when the same soil conditions become favourable to plant growth. The result is that more nutrients get used up by the pasture or crop rather than wasted.
Benefits of reduced solubility
For both PCU and dicalcic phosphate, the reduced solubility has proven so successful that less nutrient need be applied to meet pasture and crop needs. If less is needed, application costs are reduced.
Another nutrient-efficient strategy the Fertiliser Industry is working towards is to manufacture fertilisers with a high nutrient content. Such products are often called ‘high analysis’ fertilisers.
Fertiliser analysis
All mineral fertilisers are lab tested for their nutrient content. Each fertiliser product is then assigned an analysis as a list of the major nutrients it contains and the percentage of that nutrient in the product. The analyses are critical because they allow us to work out how much nutrient to apply to meet each customer’s crop and pasture growth requirements.
So, for example, Fertco’s dicalcic phosphate fertiliser ‘RePlenish’ has an analysis of of P-9, S-8.3, and Ca-24. This means that it contains 9% potassium, 8.3% sulphur, and 24% calcium.
High analysis fert
According to definitions provided by the Food and Agriculture Organisation of the UN, all fertilisers guaranteed by the manufacturer to contain at least 25% plant-available nutrients can be categorised as ‘high analysis’.
Therefore Fertco’s Replenish, described above, is a ‘high analysis’ fertiliser as are most modern synthetic fertilisers.
High analysis fertilisers aren’t new. But what is new, is the technology to manufacture fertilisers with a higher nutrient content than those previously available.
For example, Fertco’s newest dicalcic phosphate, being marketed as DCP-Max, has a P content of 16.5%. This P content is significantly higher than other phosphate fertilisers currently available and a more efficient option when phosphates are needed.
This article was published in the Coast & Country News.
